Buoyant pressure vessels for gases



Jan. 16, 1962 H. H. WALKER 3,016,366

- BUOYANT PRESSURE VESSELS FOR GASES Filed Sept. 12, 196i 2 Sheets-Sheet1.

INVENTOR. HARRY H. WALKER.

AT TO RNEYS Jan. 16, 1962 H. H. WALKER 3,

BUOYANT PRESSURE VESSELS FOR GASES Filed Sept. 12, 1960 2 Sheets-Sheet 248\ 44 43 53 49 45 FIG? 47 54 I0 49 42 49\ FIGIO 40 FIGH INVENTOR. HARRYH. WALKER ATTORNEYS United States Patent Ollice 3,016,866 BUOYANTPRESSURE VESSELS FOR GASES Harry II. Walker, R0. Box 3565, Beirut.Lebanon Filed Sept. 12, 1960, Ser. No. 55,254 4 (Ilaims. (Cl. 114--74)The present invention is directed to new and useful improvement inbuoyant vessels for the transport of liquid petroleum, gaseous material,or liquified gases.

Present oceangoing tanker constructions have disadvantages in that dueto their deep draft, they must be loaded and unloaded from a deep waterpier or submarine mooring, which mooring involves running pipelines fromthe shore to the mooring point situated in deep water. These tankers arealso unsuited to carry high vapor pressure liquids, such as liquifiedpetroleum gases. The high vapor pressure of these liquids demandsdetails of construction and handling equipment quite different fromthose associated with conventional forms of liquid cargo. At the presenttime these high vapor pressure liquids are usually refrigerated to apoint where they have a low vapor pressure and can be transported as aliquid in insulated unpressurized tanks. Often times these high vaporpressure liquids are carried in independent pressure tanks in thecustomary type of cargo vessel that is fitted and arranged for thehandling thereof. Since a major portion of the cost of liquifiedpetroleum gases and liquids in general depends in a large measure on thecost of trans port, and the associated cost of handling, it is obviouslydesirable to reduce these costs to as large an extent as possible.

Accordingly, a major purpose of the present invention is the provisionof buoyant pressure vessels that are so formed as to be seagoing innature and which are also so formed as to enable simple conversion fromdeep draft vessels to extremely shallow draft vessels, thereby enablingconverson thereof in deep Water at a point close to a point of desiredlanding, at which time the vessels may simply be floated ashore, wherethey may be picked up and handled by ground equipment.

A related purpose of the invention is the formation of pressure vesselsthat can be manufactured and used in the transport of liquids orliquified petroleum gases on an economical basis.

Another related purpose of the invention is the provision of improvedtank facilities for the transport of liquids or gases, the tanks beingso arranged that they are easily towed through the water, converted atwill from deep draft vessels to shallow draft vessels, and at the sametime being such as to provide an extremely rugged and durableconstruction with the use of relatively thin walled sections throughoutthe vessel.

Another related purpose of the invention is the provision of a buoyantair chamber surrounding a vessel for the transport of liquid petroleum,or gases, or liquified gases, the chamber being so arranged that itprovides a protective shell for the container proper and at the sametime provides a ballast chamber which enables tilting of the vessel andthereby enables conversion of the vessel from a deep draft vessel to ashallow draft vessel.

Other objects and purposes will appear from time to time in the courseof the ensuing specification and claims, when taken with theaccompanying drawings, in which:

FIGURE 1 is a diagrammatic view of a string of pressure vessels formedin accordance with the present invention and being towed in deep draftposition by an oceangoing tug or the like;

FIGURE 2 is a diagrammatic view of the vessels illustrated in FIGURE 1,but illustrating these vessels in shallow draft position;

FIGURE 3 is a cross-sectional view of a typical vessel formed inaccordance with the present invention and taken along a vertical crosssection when the vessel is in its deep draft position;

FIGURE 4 is a cross-sectional view of the vessel illustrated in FIGURE3, but illustrating another position of the vessel during the tiltingaction thereof;

FIGURE 5 is a cross-sectional view of the vessel illustrated in i IGURES3 and 4, but illustrating still another position of the vessel duringthe tilting thereof;

FIGURE 6 is a cross-sectional view of the vessel illustrated in FIGURES3, 4 and 5, but illustrating the vessel in a horizontal or shallow draftposition;

FIGURE 7 is a side view of the vessel illustrated in FIGURES 3 through6, inclusive, with certain parts in section for purposes of clarity;

FIGURE 8 is a side view of vessels formed in accordance with the presentinvention and of the type illustrated in FIGURE 1;

FIGURE 9 is a cross-sectional illustration of the vessel illustrated inFIGURE 8 and taken along .a vertical plane extending through the vessel,when the vessel is in a deep draft position;

FIGURE 10 is a sectional view of the vessel illustrated in FIGURES 8 and9 and looking in the direction of the arrows lib-dil of FIGURE 9;

FIGURE 11 is a top view of the vessel illustrated in FIGURES 8, 9 and10; 7

FIGURE 12 is a view illustrating certain details of the construction ofcylindrical tubes constituting a portion of the vessel embodying thepresent invention; and

FIGURE 13 is a cross-sectional illustration of a further form ofpressure vessel constituting the present invention.

Like elements are designated by like characters throughout thespecification and drawings.

With particular reference now to the drawings and in the first instanceto FIGURE 1, numeral 26 designates a towing vessel which may be aseagoing tug. The towing vessel 20 includes a towing line 21, extendingrearwardly thereof and which is adapted to be connected to severalpressure vessels formed in accordance with the present invention, whichvessels are designated at 22.

Each of the vessels 22 may be connected, by means of the tow lines 21aand 21b, to a towing support 23, which in turn is connected by means ofthe towing line 21 to the tug 20. Towing support 23 may form a mooringbuoy for the vessels when it is desired to store them close to a shoreline.

In accordance with the invention, each of the vessels 22 has a lengthand overall height greater than their width, so they may be positionedvertically for ease in towing through the water or may be positionedgenerally horizontally for ease in floating the vessels: to a beach orshore line. The vessels may take anyone of several shapes meetingcriteria as set out herein.

In FIGURES 3 through 7, for example, the vessels 22 are illustrated asbeing generally rectangular in side outline, whereas the vessels ofFIGURE 1 are generally triangular in outline shape. In FIGURES 3 through7, the vessels are shown as including a plurality of elongatedcylindrical tanks 24 which are positioned in side by side, abuttingrelation. Inner and outer plates 25 and 26 surround the cylinders 24with the inner plates 25 fixed, as by welding, to the cylindrical sidesof the tanks 24. The outer plate 26 may be fixed to the inner plate 25and held in spaced relation thereto as by any suitable braces 27, theshowing of which is omitted in FIGURES 3, 5 and 6 for clarity. The innerand outer plates 25 and 26 thus define a protective envelope around thecylindrical. vessels 24.

Each of the vessels is adapted for communication with each other as bymeans of the connecting tubes 28. An inlet for one of the tanks 24 isdesignated at 29 and may Patented Jan. 16, 1962 include a control valve30 which may be opened for admitting or discharging contents from thetanks 24.

The envelope defined by the plates 25, 26 is divided along themid-section thereof as by means of barrier plates 31 which divide theenvelope into air spaced above and below the barrier plates 31. One sideof the vessel is provided with an air inlet fitting 32 which is adaptedto be connected to a source of air under pressure. Inlet 32 may includea valve 33 which closes the inlet to the space 31a in the envelope. Oneside of the envelope may include a discharge fitting 34 which includes avalve 35 adapted to selectively open and close this fitting, which leadsinto space 31a.

By opening the valve 35, while the valve 33 is closed, water may enterinto the ballast space 31a, thus shift the center of gravity of thevessel toward the lower end, as appears in FIGURE 3, and thus holdingthe vessel in the upright position illustrated in FIGURE 2.

By opening valve 35 and attaching fitting 32 to a source of airpressure, air will enter the space 31a and forcibly eject the watertherefrom through the valve 35. When the water has been exhausted fromthe space 31a, the valve 35 is closed. The center of gravity of thevessel then shifts back towards the mid-point thereof and the vesselwill undergo the tilting action illustrated in FIG- URES 3 through 6, soas to assume a more or less horizontal disposition in the water.

FIGURE 8 illustrates a vessel having the triangular shape illustrated inFIGURE 1 and so formed as to provide the tilting action described forthe form of the invention illustrated in FIGURES 3 through 7, inclusive.In FIGURE 8 a plurality of cylindrical tubes are used to define atriangular shape.

FIGURE 8 illustrates a triangularly shaped vessel 40 with a towingconnection 41 at the apex of the triangle at which the longer side andhypotenuse meet. As will be noted from FIGURES and 11, the vessel has anoverall length and height substantially greater than its Width, whichwidth appears in the top view of FIGURE 11. As will be particularlynoted in FIGURE 9, the vessel as defined by a plurality of cylindricaltubes 42, 43 and 44, the tube 42 forming the hypotenuse of the triangle,while the tubes 43 and 44 form the sides of the triangle. The end edgesof each of these tubes are inclined to the longitudinal axes thereof asby cutting a normal cylindrical tube along a plane inclined to the axesof these tubes. These end edges 45 are so inclined that they mate withthe edges of one another so that they may be welded together, thusforming a triangularly shaped vessel consisting of tubes incommunication with one another.

Suitable bracing may be positioned between the tubes as by means of theintermediate cylindrical tube 46 which is welded to the tubes 42 and 44as by means of a saddle joint which is illustrated in FIGURE 12. Anadditional bracing tube 47 may extend between the tube 43 defining theshort side of the triangle and the bracing tube 46 and fixed tothesetubes as by means of the saddle joint illustrated in FIGURE 12. Openingsin the side walls of the tubes 42, 43 and 44 afford communication to andfrom the tubes 46 and 47 and tubes defining the sides of the triangle.These openings should be relatively small in size so as to equalizepressure in the several tubes without materially weakening the walls ofthe tubes.

It should be noted that the pressure forces in the tubes,

which forces tend to separate the tubes at the joints, are

exerted over a relatively large welded area due to the fact that themating edges of the tubes are inclined to the longitudinal axes thereof.

The pressurevessel thus defined is enclosed by a ballast envelopedefined by inner and outer plates 48 and 49, respectively, which platesextend completely around the vessel and which define an air and ballastspace therein. The inner plates 48 are preferably welded to the sidewalls of the severaltubes enclosed in this envelope. The outerplates 49may be fixed to the inner plates and held in spaced relation thereto asby means of bracing elements 50 of the same type illustrated in FIGURES3 through 7, inclusive.

A barrier '51 is positioned between the inner and outer plates so as toseal off a space in the envelope above the barrier and below thebarrier, thus providing an air space above the barrier and a ballastspace below the barrier.

The vessel includes a suitable valved inlet fitting 52 for admittinggases or fluids to the several cylindrical tubes, a valved air inletfitting 53 leading to the ballast space beneath barrier 51, and a valvedwater inlet and outlet fitting 54 leading to the ballast space.

As is the case with the form of the invention illustrated in FIGURES 3through 7, inclusive, water may be admitted to the ballast space throughfitting 54 when valve fitting 53 is closed, and this then disposes thecenter of gravity below in the lower region of the VES E The vessel, orseveral interconnected vessels, may thcri be towed through the water inthe deep draft position which is illustrated in FIGURE 1. When a landingarea is reached, valve fitting 54 is opened and a source of air underpressure is then connected to fitting 53 so as to forcibly eject thewater from the ballast space. After ejection, fittings 53 and 54 areclosed and the center of gravity of the vessel rises therein and the yessel rolls over on its side, thereby becoming a shallow draft vessel, asillustrated in FIGURE 2, for landing purposes.

FIGURE 13 illustrates a triangularly shaped vessel similar to thatillustrated in FIGURES 8 through 12.- In FIGURE 13, however,substantially the entire space within the tubes 55, 56 and 57, whichdefine the sides and hypotenuse of the triangle, respectively, arefilled with bracing tubes which also carry liquid or gases. In FIGURE13, for example, several tubes 58, 59 and 60 are positioned in side byside abutting relation and welded to one another, and also welded to oneside of tube 55. Tubes 61 and 62 extend parallel to the tube 57 formingthe hypotenuse and have their side walls welded to one another and withone of the tubes welded to the side wall of tube 57. All of the tubes inFIGURE 13 have their end edges formed on planes inclined to thelongitudinal axes thereof, except for the end edges of the tubes 58, 5?and 6t adjoining the side tube 56. Those end edges of the interior tubeswhich adjoin the side walls of other tubes may be affixed thereto as bysuitable saddle joints of the type illustrated in FIG- URE 12.

The pressure vessel structure illustrated in FIGURE 13 also includes aballast envelope defined by inner and outer plates 48 and 49 withsuitable braces 50 and similar in all respects to the protective andballast envelope defined in FIGURES 8 through 11. The structure alsoincludes inlet and outlet fittings 52, 53 and 54 identical in allrespects to the correspondingly numbered fittings in FIGURES 8 through10.

The triangular shape of the vessels gives a streamlining effect which isadvantageous in towing.

The particular triangularly shaped pressure vessels shown herein definea continuous gas or liquid vessel which may have high strength even withrelatively thin walled tubes. In this connection, the mating edges ofthe tubes defining the triangles are so formed that the pressure forceswhich tend to separate the vessels at the joints are distributed overmuch larger areas than is the case where the ends of the cylindricaltubes are formed on planes extending perpendicularly to the axes of thetubes. The interior tube network, which may take the style illustratedin FIGURES 9 and 10, or the style illustrated in FIGURE 13, not onlyprovides additional storage space for liquids or gases, but also is soformed as to resist the outward expanding forces that work on the tubesdefining the sides of the triangle. It should be noted that since all ofthe tubes are in communication with one another, heavy end plates orcastings customarily used with cylindrical vessels are unnecessary. Asformed, the tubes, in effect, are endless, thereby attaining some of theadvantages of doughnut-shaped pressure vessels in this respect.

All forms of the invention herein described are highly advantageous inthe transport of high vapor pressure liquids or other liquids. Thevessels are so formed that when the interior tubes are substantiallyfilled with liquid, the vessels are sufiiciently buoyant as to assume ariding position in the water on their sides, or in the shallow draftposition. The center of gravity of the vessels is then at or near themidpoint thereof. When water is admitted to the ballast space, however,and the ballast space becomes filled with water, the center of gravityshifts so that the vessels assume an upright position in the Water. Whenin the upright position the vessels may be balanced so that only theupper portions thereof extend above the water line, which not onlyimproves the riding qualities of the vessels when towed through theseas, but as a corollary thereto reduces wave action on the vessels andreduces the towing power required.

The outer envelope for the vessels not only provides the air space andbuoyant space necessary for conversion thereof from deep draft vesselsto shallow draft vessels, but also provides a protective air wallsurrounding the vessels, which wall is advantageous from the standpointof protecting the vessels when they are landed on a beach and thereafterhandled.

Groups of vessels of the type herein illustrated and described may betowed together and then moored close to a point of landing andmaintained in the deep draft position. When it is desired to land thevessels, a suitable source of air pressure connected to the air inletfittings easily ejects the Water from the ballast spaces to allow thevessels to assume their shallow draft or generally horizontal positionfor landing.

The forms of vessels herein described are also highly advantageous interms of requiring relatively low tow ing power. It is a known fact thata towing vessel expends much power due to the reactive forces betweenthe wash of the propeller and the forward face of the vessel or vesselsimmediately behind the towing vessel and exposed to the wash. It is alsoknown practice to tow vessels side by side and held apart with about sixto eight inches between the sides of the vessel, so that this propellerwash will race between this space between the barges or towed vessels,and thus require less power than is the case where barges are held withtheir sides in abutting relation.

The herein described invention is highly advantageous in this respect inthat the vessels are relatively narrow and when disposed in side by siderelation, a large number of them, say eight or ten vessels, create manyspaces for the passage of this propeller wash. In other words, where twobarges or vessels having considerable width are spaced apart by six oreight inches for the passage of the propeller wash, only a singlepassage for this wash is provided; while with vessels of the typeillustrated herein, eight or ten vessels connected side by side andspaced apart from one another may represent the same storage volume astwo relatively wide vessels, while creating seven or nine spaces for thepassage of the pro peller wash. Thus, use of the vessels of the typedisclosed herein enables the creation of a large number of spaces forthe propeller wash with an attendant reduction of power required of thetowing vessel.

Whereas 1 have shown and described certain operative forms of theinvention, it should be understoodthat this showing and descriptionthereof are to be taken in an illustrative or diagrammatic sense only.There are many modifications to the invention which will fall within thescope and spirit thereof and which will be apparent to those skilled inthe art. The scope of the invention should be limited only by the scopeof the hereinafter appended claims.

I claim:

1. A vessel for the marine transport of liquid or gaseons cargoes bytowing comprising an inner tubular cargo containing structure, anenclosing outer chamber defined by spaced inner and outer skins, apartition horizontally dividing said chamber to define an upper buoyancycompartment and a lower water ballast compartment to cause the vessel tofloat in an upright position, the overall depth of the vessel beingseveral times greater than its width, means for forcing air underpressure into the ballast compartment to expel the water ballastcontained therein to cause the vessel when about to enter shallow watersto turn about a horizontal axis into a horizontal position to verymaterially reduce its draft, and means for flooding the said ballastcompartment with water when it is desired to return the vessel to anupright deep draft position.

2. A vessel as claimed in claim 1 of substantially triangular shape, thevessel being provided at the point of intersection of the hypotenusewith one side, with means for connection with a towing vessel.

3. A vessel as claimed in claim 1, wherein said vessel has an overallrectangular shape and said inner cargo containing structure is definedby a plurality of cylin drical tubes positioned in side by side relationand joined to one another, said tubes being in communication with oneanother.

4. A vessel as claimed in claim 1, wherein said vessel has an overalltriangular shape and said inner cargo containing structure is defined bya plurality of cylindrical tubes positioned in a similar triangularshape and joined to one another, said tubes being in communication withone another.

References Cited in the file of this patent UNITED STATES PATENTS933,331 Niedringhaus Sept. 7, 1909 1,176,526 Doxford Mar. 21, 19161,277,943 Keall Sept. 3, 1918 FOREIGN PATENTS 784,390 Great Britain Oct.9, 1957 821,195 Great Britain Sept. 30, 1959

